Method of making an extruded instant granular food product

ABSTRACT

A process for the production of a free flowing and instantly dispersible and/or soluble granular food product, which comprises preparing a mix of an oil or fats and powdery carbohydrates and/or protein rich materials in an extruder, plasticizing the mix in the extruder and forming the mix into granules by extruding the plasticized mix in strands and cutting the strands.

TECHNICAL FIELD

The present invention relates to a process for the production of a freeflowing and instantly dispersible and/or soluble granular food product.

BACKGROUND OF THE INVENTION

DD-A-248502 (Institut für Getreideverarbeitung) discloses a process forthe production of instant sauces or soups in the form of granules bypreparing a powdery or doughlike mixture of protein hydrolysate, meat orvegetable material, instant flour or semolina, salt, sugar and spices,granulating it with a press or with an extruder, fluidised bed coatingthe granules with oil, carbohydrates or gums and drying them.

GB-A-2131271 (Institut für Getreideverarbeitung) discloses a process forthe production of a granulated food based on milk or other animal orvegetable proteins, carbohydrates, fats and minerals which comprisesmixing powdery components in a fluidised bed and spraying a liquid mixof the remaining components into the powdery components, the powderymaterial being coated and agglomerated by the sprayed material and driedsimultaneously in the fluidized bed.

U.S. Pat. No. 5,332,585 (Odermatt et al.) discloses a process forpreparing a granular food product by mixing a molten fat with anamylaceous material, extruding the mixture in strands, cooling thestrands, subdividing them into sections and projecting the sectionsthrough a grill to reduce them into granules.

SUMMARY OF THE INVENTION

The problem addressed by the present invention was to provide a noveland simple process for the production of a free flowing and instantlydispersible and/or soluble granular food product from carbohydrates,proteins, and oil or fats.

To this end, the process according to the present invention comprisespreparing a mix of an oil or fats and powdery carbohydrates and/orprotein rich materials in an extruder, plasticizing the mix in theextruder and forming the mix into granules by extruding the plasticisedmix in strands and cutting the strands.

The process according to the present invention indeed enables a freeflowing granular food product to be produced from carbohydrates,proteins, and oil or fats which is instantly dispersible and/or solublein warm or boiling water and which is thus suitable for the preparationof instant food in pap or liquid form.

DETAILED DESCRIPTION OF THE INVENTION

Throughout the present specification and claims the expression “stableemulsion” means that a fat phase is predominantly present in form ofsmall globules homogeneously dispersed in a liquid phase without anyphase separation being observed.

The term “desintegrant” means a food grade desintegrating agent which isable to desintegrate the granules dispersed in water, by way of acapillarity effect, as far as the desintegrant containing granules werecompacted to a certain extent during forming.

The present process may start from carbohydrates, proteins and/or oil orfats in form of the components of an animal or vegetable material, suchas milk solids, cereal flour or soya flour, and/or in form of individualcomponents, such as starch, polysaccharides, maltodextrines, saccharose,lactose, glucose, egg proteins, gluten, protein concentrates or proteinisolates from milk, whey or soya, triglycerides of animal or vegetableorigin, milk fat, palm oil, palm olein, coconut oil, or rape seed oil.

Thus, it is possible to prepare a mix which comprises, in part byweights, from 5 to 95 parts, preferably from 30 to 70 parts ofcarbohydrates, up to 40 parts, preferably from 15 to 30 parts ofproteins, and up to 80 parts, preferably from 5 to 40 parts of oil orfats.

The following components may be added before and/or after preparing saidmix:

up to 25 parts, preferably up to 15 parts of water,

up to 5 parts, preferably up to 0.6 part of emulsifier, such aslecithin, mono- and/or diglycerides,

up to 3 parts, preferably up to 1 part of desintegrants, such asmodified starches, carboxymethylcellulose (CMC), formaldehyde-casein andother modified proteins,

up to 3 parts, preferably up to 1 part of stabilizers, such as pectine,xanthan and other gums,

and, optionally, vitamins, micronutrients and/or antioxidants.

For preparing said mix in an extruder, it is possible to prepare anemulsion from an oil, water and an emulsifier, and to introducesimultaneously or successively the emulsion and the powdery materialsinto the extruder.

Alternatively it is possible to prepare a mixture of an oil or fats andpowdery carbohydrates, prepare an aqueous emulsion of an oil and powderyprotein materials, and introduce simultaneously or successively themixture and the emulsion into the extruder.

The extruder may be a single screw or a twin screw extruder such as aMAPIMPIANTI or WENGER single screw extruder, or a BUHLER, WENGER,CLEXTRAL or WERNER & PFLEIDERER twin screw extruder, or a READCO typeTELEDYNE or AOUSTIN twin screw mixer.

The temperature may be adjusted in different zones of the extruder infunction of the work which is to be carried out in these zones, namelymixing (room temperature), fat melting (above about 55° C.),plasticising and/or starch gelatinizing (from about 120° C. to about180° C.). The pressure may be adjusted accordingly from aboveatmospheric pressure (mixing, fat melting) up to between about 200 kPaand about 10 MPa (plasticising, starch gelatinising, extruding), theresidence time within the extruder possibly being from about 2 s toabout 2 min.

The plasticised mixture may be extruded in strands through a die such asa plate having circular openings from about 1 to 3 mm in diameter.

The extruded strands may be cut into granules from about 2 to 5 mm inlength.

The granules thus obtained may then be dried to a residual content ofbetween about 1 to 5%, preferably between about 2 to 3.5%.

These granules may have a bulk density of from about 400 to 600 g/l.

Further forming steps such as compacting and/or spheronising may beprovided for, so that the bulk density of the granules be increased upto values between about 500 and 1000 g/l.

An embodiment of the process according to the present invention isillustrated in the following Example in which percentages and parts areby weight.

EXAMPLE

An emulsion was prepared which contained 20 parts water, 15 parts palmolein, 15 parts skimmed milk powder and 0.6 part lecithin.

This emulsion was fed into a twin screw extruder together with 25 partsof skimmed milk powder, 15 parts lactose and 10 parts corn starch.

The mix prepared in this way at room temperature in a mixing zone of theextruder was then plasticised at 140° C. under 8 MPa in a mechanicallycompressing and shearing zone of the same extruder. The plasticised mixwas extruded in strands through cylindrical openings 2 mm in diameterpierced in a die plate provided at the end of the extruder. The strandswere cut into granules 5 mm in length which had a bulk density of 500g/l.

These granules were free flowing and instantly dispersible in warm orboiling water.

What is claimed is:
 1. A process for the production of a free-flowinggranular food product consisting essentially of: preparing a mix whichcontains from 30 to 70 parts of a carbohydrate in powder form, from 15to 30 parts of a protein in powder form, and from 5 to 40 parts of anoil or fat; adding before or after preparing said mix up to 25 partswater, an emulsifier in an amount of no more than 5 parts, adisintegrant in an amount of no more than 3 parts, and a stabilizer inan amount of no more than 3 parts; and plasticizing the mix by heatingfor between 2 seconds and 2 minutes at a temperature of between 120° C.and 180° C. and a pressure of between about 200 kPa and 10 MPa;extruding the plasticized mix to form strands; and cutting the strandsinto granules which are instantly dispersible in warm or boiling water.2. The process of claim 1, wherein an emulsion from the oil or fat,water, and emulsifier is prepared and added to the carbohydrate andprotein to prepare the mix.
 3. The process of claim 2 wherein thesoluble granular food products has a bulk density of from about 400 toabout 600 grams per liter.
 4. The process of claim 1 wherein a mixtureof the oil or fat and carbohydrate is prepared and an aqueous emulsionof an oil and the protein is prepared before forming the mix bycombining the aqueous emulsion and mixture.
 5. The process of claim 1,wherein the soluble granular food products has a bulk density of fromabout 400 to about 600 grams per liter.
 6. The process of claim 1,further comprising the step of compacting and/or spheronising, whereinthe soluble granular food product has a bulk density of from about 500to about 1000 grams per liter.
 7. The process of claim 2, wherein thesoluble granular food product is compacted to a bulk density of fromabout 500 to about 1000 grams per liter.